Re: [PATCH v3 6/7] tests/qtest: Add API functions to capture IRQ toggling

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 7/1/25 19:35, Philippe Mathieu-Daudé wrote:
> Cc'ing maintainers:
> 
> $ ./scripts/get_maintainer.pl -f tests/qtest/libqtest.c
> Fabiano Rosas <farosas@suse.de> (maintainer:qtest)
> Laurent Vivier <lvivier@redhat.com> (maintainer:qtest)
> Paolo Bonzini <pbonzini@redhat.com> (reviewer:qtest)
> 
> On 16/12/24 15:18, Gustavo Romero wrote:
>> Currently, the QTest API does not provide a function to capture when an
>> IRQ line is raised or lowered, although the QTest Protocol already
>> reports such IRQ transitions. As a consequence, it is also not possible
>> to capture when an IRQ line is toggled. Functions like qtest_get_irq()
>> only read the current state of the intercepted IRQ lines, which is
>> already high (or low) when the function is called if the IRQ line is
>> toggled. Therefore, these functions miss the IRQ line state transitions.
>>
>> This commit introduces two new API functions:
>> qtest_get_irq_raised_counter() and qtest_get_irq_lowered_counter().
>> These functions allow capturing the number of times an observed IRQ line
>> transitioned from low to high state or from high to low state,
>> respectively.
>>
>> When used together, these new API functions then allow checking if one
>> or more pulses were generated (indicating if the IRQ line was toggled).
>>
>> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> Acked-by: Thomas Huth <thuth@redhat.com>
>> ---
>>   tests/qtest/libqtest.c | 24 ++++++++++++++++++++++++
>>   tests/qtest/libqtest.h | 28 ++++++++++++++++++++++++++++
>>   2 files changed, 52 insertions(+)


>> +uint64_t qtest_get_irq_raised_counter(QTestState *s, int num)
>> +{
>> +    /* dummy operation in order to make sure irq is up to date */
>> +    qtest_inb(s, 0);
> 
> Isn't it better to simply call:
> 
>         qtest_rsp(s);
> 
> ?

Sorry I misunderstood. You want to flush the qtest socket, right?
Could this be sufficient?

           s->ops.send(s, "\n");

Otherwise I'd rather add a "nop" command. Seeing "inb" in traces
is very confusing.

> 
>> +
>> +    return s->irq_raised_counter[num];
>> +}